diff --git a/lib/Frontend/CompilerInstance.cpp b/lib/Frontend/CompilerInstance.cpp
index 0ff70ed..fa5338d 100644
--- a/lib/Frontend/CompilerInstance.cpp
+++ b/lib/Frontend/CompilerInstance.cpp
@@ -255,6 +255,8 @@
   llvm::OwningPtr<ExternalASTSource> Source;
   Source.reset(createPCHExternalASTSource(Path, getHeaderSearchOpts().Sysroot,
                                           getPreprocessor(), getASTContext()));
+  // Remember the PCHReader, but in a non-owning way.
+  Reader = static_cast<PCHReader*>(Source.get());
   getASTContext().setExternalSource(Source);
 }